[PATCH 0/2] iio: mxs-lradc: fixes

[PATCH 0/2] iio: mxs-lradc: fixes

[Robert Hodaszi]

Hello,

The following patches are fixing some bugs in the MXS LRADC driver.

Note, that I tried the patches on a custom i.MX28 based module. I did not try
them on i.MX23.

The first patch fixes the analog voltage divider.

The second patch adds back the channel 9 to fix the LRADC channel indexes.
(E.g. currently the <&lradc 12> refers to the channel 13.)

Robert Hodaszi (2):
  iio: mxs-lradc: fix divider
  iio: mxs-lradc: add ADC channel 9 as a copy of channel 8

 drivers/staging/iio/adc/mxs-lradc.c | 73 ++++++++++++++++++++++---------------
 1 file changed, 43 insertions(+), 30 deletions(-)

[PATCH 1/2] iio: mxs-lradc: fix divider

[Robert Hodaszi]

All channels' single measurement are happening on CH 0. So enabling / disabling
the divider once is not enough, because it has impact on all channels.

Set only a flag, then check this on each measurement, and enable / disable the
divider as required.

Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
---
 drivers/staging/iio/adc/mxs-lradc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index dae8d1a..52d7517 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -846,6 +846,14 @@ static int mxs_lradc_read_single(struct iio_dev *iio_dev, int chan, int *val)
 			LRADC_CTRL1);
 	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
 
+	/* Enable / disable the divider per requirement */
+	if (test_bit(chan, &lradc->is_divided))
+		mxs_lradc_reg_set(lradc, 1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
+			LRADC_CTRL2);
+	else
+		mxs_lradc_reg_clear(lradc,
+			1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET, LRADC_CTRL2);
+
 	/* Clean the slot's previous content, then set new one. */
 	mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(0),
 			LRADC_CTRL4);
@@ -961,15 +969,11 @@ static int mxs_lradc_write_raw(struct iio_dev *iio_dev,
 		if (val == scale_avail[MXS_LRADC_DIV_DISABLED].integer &&
 		    val2 == scale_avail[MXS_LRADC_DIV_DISABLED].nano) {
 			/* divider by two disabled */
-			writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
-			       lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_CLR);
 			clear_bit(chan->channel, &lradc->is_divided);
 			ret = 0;
 		} else if (val == scale_avail[MXS_LRADC_DIV_ENABLED].integer &&
 			   val2 == scale_avail[MXS_LRADC_DIV_ENABLED].nano) {
 			/* divider by two enabled */
-			writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
-			       lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_SET);
 			set_bit(chan->channel, &lradc->is_divided);
 			ret = 0;
 		}

[PATCH 2/2] iio: mxs-lradc: add ADC channel 9 as a copy of channel 8

[Robert Hodaszi]

Commit c8231a9af8147f8a401fc55931ec44abfb937660 ("iio: mxs-lradc: compute
temperature from channel 8 and 9") merged channel 8 and channel 9 to create an
IIO_TEMP channel. It changed the number of LRADC channels, which could cause
incompatibility with previous device-tree declarations, and also makes it
illogical (e.g. channel 15 is <&lradc 14>).

Add channel 9 as a copy of channel 8. Reading channel 9 has the same output as
reading channel 8.

Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
---
 drivers/staging/iio/adc/mxs-lradc.c | 61 +++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index 52d7517..25c0519 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -1376,8 +1376,8 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
  * Driver initialization
  */
 
-#define MXS_ADC_CHAN(idx, chan_type) {				\
-	.type = (chan_type),					\
+#define MXS_ADC_VOLTAGE_CHAN(idx) {				\
+	.type = IIO_VOLTAGE,					\
 	.indexed = 1,						\
 	.scan_index = (idx),					\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
@@ -1391,32 +1391,41 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
 	},							\
 }
 
+#define MXS_ADC_TEMP_CHAN(idx) {				\
+	.type = IIO_TEMP,					\
+	.indexed = 1,						\
+	.scan_index = (idx),					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			      BIT(IIO_CHAN_INFO_SCALE) |	\
+			      BIT(IIO_CHAN_INFO_OFFSET),	\
+	.channel = (idx),					\
+	.address = (idx),					\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = 18,					\
+		.storagebits = 32,				\
+	},							\
+}
+
 static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
-	MXS_ADC_CHAN(0, IIO_VOLTAGE),
-	MXS_ADC_CHAN(1, IIO_VOLTAGE),
-	MXS_ADC_CHAN(2, IIO_VOLTAGE),
-	MXS_ADC_CHAN(3, IIO_VOLTAGE),
-	MXS_ADC_CHAN(4, IIO_VOLTAGE),
-	MXS_ADC_CHAN(5, IIO_VOLTAGE),
-	MXS_ADC_CHAN(6, IIO_VOLTAGE),
-	MXS_ADC_CHAN(7, IIO_VOLTAGE),	/* VBATT */
+	MXS_ADC_VOLTAGE_CHAN(0),
+	MXS_ADC_VOLTAGE_CHAN(1),
+	MXS_ADC_VOLTAGE_CHAN(2),
+	MXS_ADC_VOLTAGE_CHAN(3),
+	MXS_ADC_VOLTAGE_CHAN(4),
+	MXS_ADC_VOLTAGE_CHAN(5),
+	MXS_ADC_VOLTAGE_CHAN(6),
+	MXS_ADC_VOLTAGE_CHAN(7),	/* VBATT */
 	/* Combined Temperature sensors */
-	{
-		.type = IIO_TEMP,
-		.indexed = 1,
-		.scan_index = 8,
-		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
-				      BIT(IIO_CHAN_INFO_OFFSET) |
-				      BIT(IIO_CHAN_INFO_SCALE),
-		.channel = 8,
-		.scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
-	},
-	MXS_ADC_CHAN(10, IIO_VOLTAGE),	/* VDDIO */
-	MXS_ADC_CHAN(11, IIO_VOLTAGE),	/* VTH */
-	MXS_ADC_CHAN(12, IIO_VOLTAGE),	/* VDDA */
-	MXS_ADC_CHAN(13, IIO_VOLTAGE),	/* VDDD */
-	MXS_ADC_CHAN(14, IIO_VOLTAGE),	/* VBG */
-	MXS_ADC_CHAN(15, IIO_VOLTAGE),	/* VDD5V */
+	MXS_ADC_TEMP_CHAN(8),
+	/* CH 9 is the same as CH 8. Declared to fix following channel indexes */
+	MXS_ADC_TEMP_CHAN(9),
+	MXS_ADC_VOLTAGE_CHAN(10),	/* VDDIO */
+	MXS_ADC_VOLTAGE_CHAN(11),	/* VTH */
+	MXS_ADC_VOLTAGE_CHAN(12),	/* VDDA */
+	MXS_ADC_VOLTAGE_CHAN(13),	/* VDDD */
+	MXS_ADC_VOLTAGE_CHAN(14),	/* VBG */
+	MXS_ADC_VOLTAGE_CHAN(15),	/* VDD5V */
 };
 
 static int mxs_lradc_hw_init(struct mxs_lradc *lradc)

Re: [PATCH 1/2] iio: mxs-lradc: fix divider

[Alexandre Belloni]

On 10/06/2014 at 15:41:34 +0200, Robert Hodaszi wrote :
> All channels' single measurement are happening on CH 0. So enabling / disabling
> the divider once is not enough, because it has impact on all channels.
> 
> Set only a flag, then check this on each measurement, and enable / disable the
> divider as required.
> 
> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>

It makes perfect sense.

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

> ---
>  drivers/staging/iio/adc/mxs-lradc.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index dae8d1a..52d7517 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -846,6 +846,14 @@ static int mxs_lradc_read_single(struct iio_dev *iio_dev, int chan, int *val)
>  			LRADC_CTRL1);
>  	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
>  
> +	/* Enable / disable the divider per requirement */
> +	if (test_bit(chan, &lradc->is_divided))
> +		mxs_lradc_reg_set(lradc, 1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
> +			LRADC_CTRL2);
> +	else
> +		mxs_lradc_reg_clear(lradc,
> +			1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET, LRADC_CTRL2);
> +
>  	/* Clean the slot's previous content, then set new one. */
>  	mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(0),
>  			LRADC_CTRL4);
> @@ -961,15 +969,11 @@ static int mxs_lradc_write_raw(struct iio_dev *iio_dev,
>  		if (val == scale_avail[MXS_LRADC_DIV_DISABLED].integer &&
>  		    val2 == scale_avail[MXS_LRADC_DIV_DISABLED].nano) {
>  			/* divider by two disabled */
> -			writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
> -			       lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_CLR);
>  			clear_bit(chan->channel, &lradc->is_divided);
>  			ret = 0;
>  		} else if (val == scale_avail[MXS_LRADC_DIV_ENABLED].integer &&
>  			   val2 == scale_avail[MXS_LRADC_DIV_ENABLED].nano) {
>  			/* divider by two enabled */
> -			writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
> -			       lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_SET);
>  			set_bit(chan->channel, &lradc->is_divided);
>  			ret = 0;
>  		}

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

Re: [PATCH 2/2] iio: mxs-lradc: add ADC channel 9 as a copy of channel 8

[Alexandre Belloni]

On 10/06/2014 at 15:41:35 +0200, Robert Hodaszi wrote :
> Commit c8231a9af8147f8a401fc55931ec44abfb937660 ("iio: mxs-lradc: compute
> temperature from channel 8 and 9") merged channel 8 and channel 9 to create an
> IIO_TEMP channel. It changed the number of LRADC channels, which could cause
> incompatibility with previous device-tree declarations, and also makes it
> illogical (e.g. channel 15 is <&lradc 14>).
> 
> Add channel 9 as a copy of channel 8. Reading channel 9 has the same output as
> reading channel 8.
> 
> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

> ---
>  drivers/staging/iio/adc/mxs-lradc.c | 61 +++++++++++++++++++++----------------
>  1 file changed, 35 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index 52d7517..25c0519 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -1376,8 +1376,8 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
>   * Driver initialization
>   */
>  
> -#define MXS_ADC_CHAN(idx, chan_type) {				\
> -	.type = (chan_type),					\
> +#define MXS_ADC_VOLTAGE_CHAN(idx) {				\
> +	.type = IIO_VOLTAGE,					\
>  	.indexed = 1,						\
>  	.scan_index = (idx),					\
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
> @@ -1391,32 +1391,41 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
>  	},							\
>  }
>  
> +#define MXS_ADC_TEMP_CHAN(idx) {				\
> +	.type = IIO_TEMP,					\
> +	.indexed = 1,						\
> +	.scan_index = (idx),					\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
> +			      BIT(IIO_CHAN_INFO_SCALE) |	\
> +			      BIT(IIO_CHAN_INFO_OFFSET),	\
> +	.channel = (idx),					\
> +	.address = (idx),					\
> +	.scan_type = {						\
> +		.sign = 'u',					\
> +		.realbits = 18,					\
> +		.storagebits = 32,				\
> +	},							\
> +}
> +
>  static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
> -	MXS_ADC_CHAN(0, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(1, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(2, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(3, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(4, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(5, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(6, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(7, IIO_VOLTAGE),	/* VBATT */
> +	MXS_ADC_VOLTAGE_CHAN(0),
> +	MXS_ADC_VOLTAGE_CHAN(1),
> +	MXS_ADC_VOLTAGE_CHAN(2),
> +	MXS_ADC_VOLTAGE_CHAN(3),
> +	MXS_ADC_VOLTAGE_CHAN(4),
> +	MXS_ADC_VOLTAGE_CHAN(5),
> +	MXS_ADC_VOLTAGE_CHAN(6),
> +	MXS_ADC_VOLTAGE_CHAN(7),	/* VBATT */
>  	/* Combined Temperature sensors */
> -	{
> -		.type = IIO_TEMP,
> -		.indexed = 1,
> -		.scan_index = 8,
> -		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> -				      BIT(IIO_CHAN_INFO_OFFSET) |
> -				      BIT(IIO_CHAN_INFO_SCALE),
> -		.channel = 8,
> -		.scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
> -	},
> -	MXS_ADC_CHAN(10, IIO_VOLTAGE),	/* VDDIO */
> -	MXS_ADC_CHAN(11, IIO_VOLTAGE),	/* VTH */
> -	MXS_ADC_CHAN(12, IIO_VOLTAGE),	/* VDDA */
> -	MXS_ADC_CHAN(13, IIO_VOLTAGE),	/* VDDD */
> -	MXS_ADC_CHAN(14, IIO_VOLTAGE),	/* VBG */
> -	MXS_ADC_CHAN(15, IIO_VOLTAGE),	/* VDD5V */
> +	MXS_ADC_TEMP_CHAN(8),
> +	/* CH 9 is the same as CH 8. Declared to fix following channel indexes */
> +	MXS_ADC_TEMP_CHAN(9),
> +	MXS_ADC_VOLTAGE_CHAN(10),	/* VDDIO */
> +	MXS_ADC_VOLTAGE_CHAN(11),	/* VTH */
> +	MXS_ADC_VOLTAGE_CHAN(12),	/* VDDA */
> +	MXS_ADC_VOLTAGE_CHAN(13),	/* VDDD */
> +	MXS_ADC_VOLTAGE_CHAN(14),	/* VBG */
> +	MXS_ADC_VOLTAGE_CHAN(15),	/* VDD5V */
>  };
>  
>  static int mxs_lradc_hw_init(struct mxs_lradc *lradc)

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

Re: [PATCH 1/2] iio: mxs-lradc: fix divider

[Marek Vasut]

On Tuesday, June 10, 2014 at 03:41:34 PM, Robert Hodaszi wrote:
> All channels' single measurement are happening on CH 0. So enabling /
> disabling the divider once is not enough, because it has impact on all
> channels.
> 
> Set only a flag, then check this on each measurement, and enable / disable
> the divider as required.
> 
> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>

Acked-by: Marek Vasut <marex@denx.de>

Best regards,
Marek Vasut

Re: [PATCH 2/2] iio: mxs-lradc: add ADC channel 9 as a copy of channel 8

[Marek Vasut]

On Tuesday, June 10, 2014 at 03:41:35 PM, Robert Hodaszi wrote:
> Commit c8231a9af8147f8a401fc55931ec44abfb937660 ("iio: mxs-lradc: compute
> temperature from channel 8 and 9") merged channel 8 and channel 9 to create
> an IIO_TEMP channel. It changed the number of LRADC channels, which could
> cause incompatibility with previous device-tree declarations, and also
> makes it illogical (e.g. channel 15 is <&lradc 14>).
> 
> Add channel 9 as a copy of channel 8. Reading channel 9 has the same output
> as reading channel 8.
> 
> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
> ---

[...]

>  static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
> -	MXS_ADC_CHAN(0, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(1, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(2, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(3, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(4, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(5, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(6, IIO_VOLTAGE),
> -	MXS_ADC_CHAN(7, IIO_VOLTAGE),	/* VBATT */
> +	MXS_ADC_VOLTAGE_CHAN(0),
> +	MXS_ADC_VOLTAGE_CHAN(1),
> +	MXS_ADC_VOLTAGE_CHAN(2),
> +	MXS_ADC_VOLTAGE_CHAN(3),
> +	MXS_ADC_VOLTAGE_CHAN(4),
> +	MXS_ADC_VOLTAGE_CHAN(5),
> +	MXS_ADC_VOLTAGE_CHAN(6),
> +	MXS_ADC_VOLTAGE_CHAN(7),	/* VBATT */
>  	/* Combined Temperature sensors */
> -	{
> -		.type = IIO_TEMP,
> -		.indexed = 1,
> -		.scan_index = 8,
> -		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> -				      BIT(IIO_CHAN_INFO_OFFSET) |
> -				      BIT(IIO_CHAN_INFO_SCALE),
> -		.channel = 8,
> -		.scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
> -	},

I wonder, shouldn't the IIO framework handle this kind of a "hole" in the 
iio_chan_spec structure, where one entry has .channel = N and the subsequent one 
has .channel = N + 2 somehow ?

> -	MXS_ADC_CHAN(10, IIO_VOLTAGE),	/* VDDIO */
> -	MXS_ADC_CHAN(11, IIO_VOLTAGE),	/* VTH */
> -	MXS_ADC_CHAN(12, IIO_VOLTAGE),	/* VDDA */
> -	MXS_ADC_CHAN(13, IIO_VOLTAGE),	/* VDDD */
> -	MXS_ADC_CHAN(14, IIO_VOLTAGE),	/* VBG */
> -	MXS_ADC_CHAN(15, IIO_VOLTAGE),	/* VDD5V */

[...]

Re: [PATCH 2/2] iio: mxs-lradc: add ADC channel 9 as a copy of channel 8

[Jonathan Cameron]

On 10/06/14 23:51, Marek Vasut wrote:
> On Tuesday, June 10, 2014 at 03:41:35 PM, Robert Hodaszi wrote:
>> Commit c8231a9af8147f8a401fc55931ec44abfb937660 ("iio: mxs-lradc: compute
>> temperature from channel 8 and 9") merged channel 8 and channel 9 to create
>> an IIO_TEMP channel. It changed the number of LRADC channels, which could
>> cause incompatibility with previous device-tree declarations, and also
>> makes it illogical (e.g. channel 15 is <&lradc 14>).

The binding is current just against an index of available channels.  If the
device does something faintly crazy with its numbering then holes will occur.

Anyhow, suggestion below on how to create a 'gap' in the channel index.

Honestly the binding is pretty hideous, but we'll have to maintain it
for a long time when someone (i.e. not me ;) comes up with a better binding
for iio consumer channels.  The non device tree one is much nicer in that
everything is done by name rather than artificial indexes.

>>
>> Add channel 9 as a copy of channel 8. Reading channel 9 has the same output
>> as reading channel 8.
>>
>> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
>> ---
>
> [...]
>
>>   static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
>> -	MXS_ADC_CHAN(0, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(1, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(2, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(3, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(4, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(5, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(6, IIO_VOLTAGE),
>> -	MXS_ADC_CHAN(7, IIO_VOLTAGE),	/* VBATT */
>> +	MXS_ADC_VOLTAGE_CHAN(0),
>> +	MXS_ADC_VOLTAGE_CHAN(1),
>> +	MXS_ADC_VOLTAGE_CHAN(2),
>> +	MXS_ADC_VOLTAGE_CHAN(3),
>> +	MXS_ADC_VOLTAGE_CHAN(4),
>> +	MXS_ADC_VOLTAGE_CHAN(5),
>> +	MXS_ADC_VOLTAGE_CHAN(6),
>> +	MXS_ADC_VOLTAGE_CHAN(7),	/* VBATT */
>>   	/* Combined Temperature sensors */
>> -	{
>> -		.type = IIO_TEMP,
>> -		.indexed = 1,
>> -		.scan_index = 8,
>> -		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> -				      BIT(IIO_CHAN_INFO_OFFSET) |
>> -				      BIT(IIO_CHAN_INFO_SCALE),
>> -		.channel = 8,
>> -		.scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
>> -	},
>
> I wonder, shouldn't the IIO framework handle this kind of a "hole" in the
> iio_chan_spec structure, where one entry has .channel = N and the subsequent one
> has .channel = N + 2 somehow ?
Hmm. This binding isn't all that heavily used as yet so this is the first time I've come across
anyone wanting to jump a channel.  Anyhow, simply having a channel with scan_index = -1
(not available for buffered capture) and nothing in any of the info_mask elements should
instantiate a channel with no actual interfaces or apparent existence.
(not that I've actually tested both of these being true as we only have
either channels that are not buffered, or devices with channels that are only buffered using
these two bits of functionality).

I'd rather this solution than adding an artificial bonus channel.

>
>> -	MXS_ADC_CHAN(10, IIO_VOLTAGE),	/* VDDIO */
>> -	MXS_ADC_CHAN(11, IIO_VOLTAGE),	/* VTH */
>> -	MXS_ADC_CHAN(12, IIO_VOLTAGE),	/* VDDA */
>> -	MXS_ADC_CHAN(13, IIO_VOLTAGE),	/* VDDD */
>> -	MXS_ADC_CHAN(14, IIO_VOLTAGE),	/* VBG */
>> -	MXS_ADC_CHAN(15, IIO_VOLTAGE),	/* VDD5V */
>
> [...]
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Re: [PATCH 1/2] iio: mxs-lradc: fix divider

[Jonathan Cameron]

On 10/06/14 23:47, Marek Vasut wrote:
> On Tuesday, June 10, 2014 at 03:41:34 PM, Robert Hodaszi wrote:
>> All channels' single measurement are happening on CH 0. So enabling /
>> disabling the divider once is not enough, because it has impact on all
>> channels.
>>
>> Set only a flag, then check this on each measurement, and enable / disable
>> the divider as required.
>>
>> Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
>
> Acked-by: Marek Vasut <marex@denx.de>
Applied to the fixes-togreg branch of iio.git
Also marked for stable.
>
> Best regards,
> Marek Vasut
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